Oral and Poster Abstracts

Conclusions The sanitation program reduced the antibiotic cost by
50%, gave less BRD signs and 29% less seropositive animals. The
program must be continued until the M. bovis herd prevalence has
dropped to an acceptable level.
Key words: Mycoplasma bovis, enrofloxacin, biosecurity
643 Analysis of Pathways for Release of Rift Valley Fever Virus
into the Continental United States
R. Kasari 1 , A. Carr 2 , V. Lynn 3 , T. Weaver 3
1
USDA-APHIS-VS-CEAH, National Surveillance Unit, Fort Collins,
United States
2
Uniformed Services University of the Health Sciences, Department
of Preventive Medicine and Biometrics, Bethesda, United States
3
USDA-APHIS-VS-CEAH, Center for Emerging Issues, Fort Collins,
United States
Objectives of Study: The primary objectives of this study were to evaluate
the feasibility of RVFV to enter the continental United States by various
routes as well as identify the states whose domestic and wild ruminant and
human populations are most vulnerable for exposure to this virus.
Materials and Methods: Pathways analysis methods were used to
identify the pathways for release of RVFV into the continental United
States. Initially, the agent, host, and environmental factors important in
the epidemiology of RVF were used to develop a list of potential
pathways for release of RVFV into the continental United States. Five
pathways were identified: (1) importation of RVFV-infected animals,
(2) entry of RVFV-infected people, (3) mechanical transport of RVFVinfected
insect vectors, (4) intercontinental wind-borne transport of
RVFV or RVFV-infected insect vectors, and (5) smuggling of live
virus. Next, the feasibility of each pathway was evaluated using data
from governmental and public domain sources to evaluate animals,
commodities, and people that moved from RVF-endemic countries to
the continental United States between calendar years 2000 and 2005.
Finally, entry points of each feasible pathway into the continental
United States were used to identify the domestic and wild ruminant and
human populations at risk for exposure to RVFV.
Results: Feasible pathways for entry of RVFV into the continental
United States are (1) importation of RVFV-infected animals, (2) entry
of RVFV-infected people, (3) mechanical transport of RVFV-infected
insect vectors, and (5) smuggling of live virus.
Conclusions: A pathways analysis provides the requisite information
needed to construct an effective targeted surveillance plan for this virus
in order to enable rapid detection and response by animal health and
public health officials. Domestic ruminant livestock, ruminant wildlife,
and people in 14 states (Alabama, California, Florida, Georgia, Maine,
Maryland, Massachusetts, Minnesota, New Jersey, New York,
Pennsylvania, South Carolina, Texas, and Virginia) appear to be most
vulnerable to exposure from RVFV. It should be noted however, that
this group of “at-risk” states could be altered entirely, if this viral agent
is released illicitly as part of a terrorist act.
Key words: Rift Valley Fever, zoonotic disease, pathways analysis
644 Analysis of Pathways for Release of Ehrlichia ruminantium
(Heartwater) into the Continental United States
R. Kasari 1 , E. Lawrence 2 , H. Howe 2 , L. Farnsworth 2 , E. Freier 2 ,
M. James 2 , S. Miller 2
1
USDA-APHIS-VS-CEAH, National Surveillance Unit, Fort Collins,
United States
2
USDA-APHIS-VS-CEAH, Center for Emerging Issues, Fort Collins,
United States
Objectives of Study: The objective of this study was to evaluate the
feasibility of Ehrlichia Ruminantium by itself or via E. Ruminantiuminfected
Amblyomma spp. vector ticks to enter the continental United
States by various routes as well as identify the States whose domestic and
wild ruminant populations are most vulnerable for exposure to this
rickettsial organism.
Materials and Methods: Pathways analysis methods were used to
identify the pathways for release of E. ruminantium into the continental
United States. Initially, the agent, host, and environmental factors
important in the epidemiology of E. ruminantium infections in susceptible
animal species were used to develop a list of potential pathways for
release of this rickettsial agent into the continental United States. Five
pathways were identified: (1) importation of E. ruminantium-infected
animal species, (2) migrating cattle egrets (Bubulcus ibis) serving as a
86 XXV. Jubilee World Buiatrics Congress 2008
transport host for E. ruminantium-infected Amblyomma spp. ticks, (3)
mechanical transport of E. ruminantium-infected Amblyomma spp. ticks
by humans and imported non-ruminant animals, reptiles, and other birds,
(4) mechanical transport of E. ruminantium-infected Amblyomma spp.
tick by fomites, and (5) smuggling of live E. ruminantium. Next, the
feasibility of each pathway was evaluated using data from governmental
and public domain sources to evaluate animals, commodities, and people
that moved from heartwater-endemic African and Caribbean island
countries to the continental United States between calendar years 2000
and 2006. Finally, entry points of each feasible pathway were used to
identify the States whose domestic and wild ruminant populations were at
greatest risk for exposure to E. ruminantium.
Results: All five pathways were feasible ones for entry of E.
ruminantium or E. Ruminantium-infected Amblyomma spp. vector ticks
into the continental United States.
Conclusions: Compared to other states, ruminant livestock and
ruminant wildlife species in 17 states (Alabama, California, Florida,
Georgia, Illinois, Louisiana, Massachusetts, Maryland, Minnesota,
Mississippi, North Carolina, New Jersey, New York, Pennsylvania,
South Carolina, Texas, Virginia) should be most vulnerable to exposure
to Amblyomma spp. ticks, some of which could be infected with E.
ruminantium. This group of “at-risk” states could be altered entirely, if
the rickettsial agent is released illicitly as part of a terrorist act.
Key words: heartwater, Ehrlichia ruminantium, pathways analysis
645 Epidemic of Bovine Viral Diarrhea Virus (BVDV) Infection
Originated from 3 Persistently Infected Cattle on a Farm
during a 5-year Period
M. Tajima 1 , K. Sano 2
1 Hokkaido University, Veterinary Teaching Hospital, Sapporo, Japan
2 NOSAI Iburi, West branch, Toya, Japan
Bovine viral diarrhea virus (BVDV) is distributed all over the world.
Persistently infected cattle with BVDV (PI) are a latent source of infection
of BVDV in the herd, and can cause serious economic damage. Testing
and culling of PI are important procedures for dairy production. We
encountered 3 outbreaks of BVDV infection in a farm during a 5-year
period, and these were suspected to have caused by 3 individual PI. First
epidemic: In May 2002, a 6-month-old Holstein calf was diagnosed as PI
because of mucosal disease. A sister cow (primipara) of the PI calf and
their dam (PI-1) were diagnosed as PI, and the bulk tank milk (BTM) test
was positive for BVDV. After exclusion of all PIs, BTM test became
negative for BVDV. The negative results were obtained twice at an
interval of 6 months, therefore, the test of BVDV was discontinued.
Second epidemic: In January 2005, 2 calves (pneumonia and poorgrowth)
were diagnosed as PI. Their dams were BVDV negative and
BTM test was positive again for BVDV. All cattle on the farm were
examined for BVDV. Six PIs were detected, a milking cow imported from
the cattle market in May 2004 (PI-2), 4 Holstein calves and a beef calf. By
examination of all neonatal calves thereafter, 14 PIs were identified during
a 6-month period. During this period, 50 milking cows were imported into
the farm. All of these animals were BVDV negative, but 5 calves
produced from these cows were diagnosed as PI. Except for these 5
calves, 9 calves and PI-2 were infected with the same BVDV based on the
analysis of E2 diversity of the isolated BVDV, however, the BVDV
differed from that involved in the first epidemic on the farm. After
exclusion of all PIs, there were no PIs for a 3-month period. Third
epidemic: In October 2005, an imported dam (PI-3) and neonatal calf
were diagnosed as PI. At this time, the importation of cattle was
discontinued, and the examination of newborn calves for BVDV was
continued. After 6 months, 2 PIs were detected. All 4 PIs were infected
with the same BVDV, and BVDV from PI-3 differed from those of PI-1
and -2. After the final detection of PI, approximately 250 newborn calves
were examined for PI during a one-year period (till May 2007). There
were no PIs and BTM test was negative every 6 months; therefore, the
farm was recognized as BVDV free. Continuous BTM test and
examination of newborn calves are the most important and effective
procedures for BVDV eradication.
Key words: BVDV, eradication, test and cull
646 Paraclinical Findings of Chronic Extensive Peritonitis in a
Diarrheic Young Calf
N. Atyabi, N. Alidadi, M. Hashemian
Faculty of Veterinary Medicine, University of Tehran, Animal
Science, Tehran, Iran